You missed d101 Games' OQ supplement, River of Heaven. Luther Arkwright (also TDM/Mythras) is sci-fi. And there's a bit more in Chaosium's Monographs (including the Icarus setting now in Cthulhu Through the Ages... but this is a valid complaint, IMHO.
Honestly, though... I don't find sci-fi to be the place where BRP-derived systems shine: in combat, modern weapons already render all humans into "mook-level" characters -- mostly we drop in one hit. Not necessarily dead, but hors de combat. And the weapons are only getting more-effective. This isn't the play-space where BRP shows to best advantage, IMHO; it's no worse than d20Modern or other D&D versions, but it doesn't stand out as notably better, either.
Still, given various other products in the extended BRP family, it seems like something Chaosium could look at. A solid sci-fi entry would nicely extend Chaosium's RPG offerings. All they need is time and staff... And/or a freelancer who submits a killer product that Chaosium finds they HAVE to print...

It's also worth pointing out...
Many companies have multiple lines/systems. Take EvilHat... mostly Fate, but they also offer Monster of the Week (a PbtA game), and Gumshoe-driven Bubblegumshoe; and even within their Fate line they have multiple variants on sale. Take OnyxPath... mostly Storyteller, but Scarred Lands is D&D (originally d20, now 5e), Pugmire is another D&D-variant, and the "Deimos" system for Cavaliers of Mars. And of course Storyteller has many variants: both WoD & CoD plus Scion, Trinity, Exalted, etc... Etc etc etc. They are all obviously doing the wrong thing.
I think it's an asset to both Chaosium and Glorantha to have both a narrative-centric ruleset like HQ and a crunchy/simulationist ruleset like RQ.
You also missed complaining about 13G: "13th Age in Glorantha" (13th Age is another d20 variant) being the THIRD completely-different gamesystem (alongside RQ and HQ) to run Glorantha.
And in addition to Mythras from TDM, we must also suffer OpenQuest &c from d101, the Renaissance line from C&W, RD100 from Alephtar, MRQ Legend, RDP Q21, d00Lite, GORE, Open Basic, and likely more I've forgotten or overlooked.
The problem is obviously even worse than you thought!
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Seriously: the stuff that seems to be bothering you is actually a reflection of the strength of BRP and its presence within the overall RPG market.
(And for the record, HQ has both a generic engine (HQ2) and a specific Glorantha version, each as a standalone product.)

This.
First came the Dragonkill; later, the Dragonrise. I expect there was some element of "srsly? dudes, wtf? r u RLLY gonna PO dragonkind AGAIN? k, whatevs... we r DONE w this shit. FIAT FORMIDO. I'm out. Thanks for the snack, btw..." YGMV, but IMG the Brown Dragon has made it part of the universe that Fear of Dragons is just a common piece of human nature near DP & Tarsh.
There IS no RW cognate to any historical event. It's now more like the RW fear of spiders, of snakes, etc. Not everyone suffers from it, and even those who do can often overcome it enough to function even around the fear-object... But it's just well-known around DP/Tarsh as a facet of human nature.

The way that I have always built support for a game is by playing it, demo'ing it. Find a FLGS or game-club, run some BRP there!
Hell, CREATE a game-club! I've created 3 clubs (2 at schools), and several non-club "gaming groups" -- just a group of players. My most-recent group began with an arc of D&D (because it was what they all knew) : hey kids, the first taste is free! Lure them in... When that arc was over, I announced that the next game *I* was running would be in a different system. It was many sessions later before anyone mentioned D&D again! 4 different GMs (2 had never GM'ed before; one had never played before our group got her gaming). Shadowrun, Call of Cthulhu, Deadlands, Ars Magica all got their licks in.
I expect the next game *I* will be running -- the next we will be playing -- will be RQG !
Go forth and GAME!

Everything the PC's can do, so can the nomads (except specialized Rune-magic). Presumably the Issaries merchant can at least ward the camp.
But I would expect any serious attempt on the caravan to be an ambush, that begins with missile fire & ranged death/incapacitation magic.
Again, I point to that HL guide, and routing through friendly territory...

Hopefully the merchant is savvy enough to pack some low-cost items to offer as tax/levy/tribute/bribe/etc to pass through Nomad country. Ideally, the Llama-rider could route them through Llama territories (and such costs would presumably be much ower).
Once well-away from Pavis, even cheap trade-goods may be high-enough value to pay their way...

Do you realize that Chaosium was in the process of going bankrupt... without ever finishing their CoC7e KickStarter? They had literally run out of money, and had no way to fulfill all their obligations!
The new owners/managers stepped in, and fronted their own personal money to complete and fulfill the KS that the prior managers had mismanaged... and now there are more than a dozen titles out for CoC 7e, plus the upcoming RQG, and many other items en train.
They are now announcing no release date for RQG because there are items remaining to complete, whose completion-time is unpredictable; and there were too many prior complaints over missing announced (obviously over-optimistic!) dates. "It'll be done when it's done" is the official policy; and honestly, that's good enough. They have recently stepped up their promo''ing, and have announced a live-play "product premiere" event streaming in a week or so; I expect this means it is coming very soon indeed!
I was one of the people complaining, previously, about them slipping on announced dates. I was perfectly willing to believe in missed deadlines and mis-estimated timeframes, I just disliked the pattern of slipped dates and only silence. I prefer their new policy; it sets the expectation in line with what they are doing: they are now living up to their promises 100%
And frankly, the new-to-RQ market won't become appreciably smaller simply by Chaosium delaying release; non-RQ players will just see it as "yet another announced-but-unreleased game," and evaluated on the reviews they read and seeing it in FLGS's when it finally does get released.

No, I was really thinking of pure-magic, not mecha-magic. But magic that crossed the lines of safety and wisdom, leaving the user more a horrific victim than mightily-empowered.
Shadowrun Cyberzombies are terrifying foes in battle, but ultimately they are tragic victims of their enhancements; similarly, Voldemort's search for ultimate security via power led him, ultimately, to complete insecurity and vulnerability (near the end of Rowling's 7th HP book, Harry has a "near-death experience" where he apparently speaks with the soul of departed Dumbledore... and whimpering in pain and terror nearby ("nearby," and thus also on the edge of death), is a horcrux-fragmented shard of Tom Riddle's soul). It is this vibe of "something that is seemingly-reasonable that is taken tragically to an artificial and unreasonable extreme" that I was thinking of, rather than any trappings of tech.
Imagine a mighty warrior in Glorantha; instead of tattoos the runes are scarified and branded into the flesh. POW-storing and other crystals aplenty; but again: not worn or wielded but magically embedded into the body. Some sites of this surgical implantation are raw suppurating wounds; some are dead and rotting; some are cracked and burned; etc. None heal, ever. None are less than horrifically agonizing.

I actually find the opposite to be "artificial" -- the idea that of course you can have multiple POW/MP storage devices.
It renders them highly artificial and "technologically flavored" to my aesthetic, like batteries to be bought at the corner market. Temp POW / MP aren't quite as central to a character as permanent POW, but they are directly linked; having multiple "devices" linked to one's permanent POW just "feels wrong" to me: you have ONE soul.
OTOH, the idea feels like it might work well in a horrible fashion as a BBG's plot, creating magitech-enhanced Gloranthan versions of Shadowrun "Cyberzombies" with elements of Potter'verse "horcruxes." Perhaps an unholy blend of Thanatari and GodLearner techniques...
I will look closely at the RQG RAW on this.

of ... Gregging?
Although I consider myself a Gloranthan Grognard (having begun in 1980 (or maybe early '81, Godtime heroquesting makes those dates vague), I haven't really been continually part of the "Gloranthan community." I never got the AH/RQ3 ruleset, only discovered the unpublished "RQ4AiG" years after it was dead and buried, etc etc etc. I've seen only a few Gregging Events occur "live" (die, Vegetarian Morocanth!), and brushed against a few more.
I'm particularly interested Greg's contributions, but more generally also most/all of the substantive revisions to the Glorantha "Canon."
Obviously the GtG has become the de facto baseline; what substantive material did it materially change?
I'm not really looking for minor tidbits. For one thing, every major change will domino innumerable little items outward. And obviously one Glroanthaphile's "major change" is another Gloranthaphiles "minor tidbit" (we shall probably en-Gern such heretics and feed them to the Morocanth).
There is the Orlanthi cultural stuff, the shift from the largely-northern-European cultural cues to mostly-Mediterranean/Middle-Eastern & hints of Vedic. There is the deprecation of the "Glorantha is Bronze Age" POV; etc etc etc... ad infinitum, it sometimes seems!
... anyone...?

It really depends on the locality!
Where I am, "Meetup.com" seems to be the preferred player-finder / organizer app. I've seen other people report that Meetup gives them no help, but reddit is useful, or Facebook.
If you have a FLGS, they often have an oldscchool corkboard or binder, and/or some online presence (either their own website, or a Meetup/FB site) which includes a player-finder / game-finder function.

Honestly, APP & the social skills can often be critical. Yeah, sure, Library is used for all sorts of research purposes... but often you need that on-the-street investigation as per a cop/reporter/PI/etc, or circulating & gossiping amongst the upper-crust as a socialite/heir/etc.
YMMobviouslyV !

it's part of the lifepath character-generation, I'm almost certain... Some people might be "Veteran's of the FHQ's cavalry" and get bonus skills for riding, mounted combat, etc; some are apprentices in various magical or religious traditions, and get associated Rune and Spirit abilities.
And from a RP perspective, she automatically gets a certain amount of social power/authority (until/unless a full priestess is around), can call upon more help/resources from temples and affiliated/allied Cults, etc etc etc. Of course, she's also got the responsibilities -- in the absence of a full Priestess on Holy Days, she will need to officiate for the community worship, etc; in the presence of a full Priestess she will be subject to her orders, etc...